The acting head of the US emergencies agency has pledged to do more to help the Hurricane Katrina survivors currently living in relief shelters.

"We're going to get people out of the shelters, we're going to move on and get them the help they need," R David Paulison told reporters.

Mr Paulison took over at the Federal Emergency Management Agency after chief Michael Brown stood down on Monday.

President Bush said responsibility for any mistakes ultimately lay with him.

"Katrina exposed serious problems in our response capability at all levels of government, and to the extent that the federal government didn't fully do its job right, I take responsibility," Mr Bush said at a news conference.